1. Field of the Invention
The present invention relates to an electric resistance sensor for measuring a corrosion rate, and in particular to an electric resistance sensor for measuring a corrosion rate not only when the primary type of corrosion is pitting but also when the corrosion rate is too late to accurately measure utilizing conventional sensors by using a plurality of conductive thin lines, a fabrication method therefor and a measurement method using the same.
2. Description of the Background Art
As a method for measuring a corrosion rate, there has been widely used method of measuring the variation in electric resistance. In this method, the resistance probes have been fabricated from materials of interest in a plate of wire shape.
In accordance with the conventional method for measuring the corrosion rate, the measuring probe is quite thick because it is mechanically processed. Therefore, a resistance variation of the probe, as a result of corrosion, is small in regard to a slight corrosion. This means that the conventional probes can not be utilized to measure the corrosion rate in cases when the corrosion rate is small. In other words, one can measure the corrosion rate only when the rate is high enough to result in a significant thickness reduction.
Consequently, there is a demand for a technique of measuring a precise corrosion rate even in an environment where the rate of corrosion is low, in order to achieve stability, precision and accuracy in maintenance and management of the facilities. The core of this demanding technology is a development of sensors having improved sensitivity and accuracy. Film-type sensors enable one to measure and monitor a slight change in corrosion behavior which can not be detected utilizing conventional plate or wire type sensors.
Accordingly, it is a primary object of the present invention to provide an electric resistance sensor in a thin film shape. This sensor includes a thin line unit consisting of a plurality of thin lines. Film-like of lines enables one not only to accurately measure a low corrosion rate but to monitor localized corrosion behaviors such as pitting and crevice. The fabrication method of film-type sensor is described in this invention.
It is another object of the present invention to provide a method for precisely measuring a corrosion rate of facilities by using an electric resistance sensor in a thin film shape.
In order to achieve the above-described objects of the present invention, there is provided an electric resistance sensor for measuring a corrosion rate including: an insulating substrate having a predetermined size; a plurality of distributing units consisting of a conductive material and formed on the insulating substrate; a plurality of connecting units formed at each one end portion of the distributing units, electrically connecting the distributing units to an external circuit, and consisting of a conductive material; a thin line unit formed between the plurality of distributing units, and having a plurality of conductive thin lines electrically connected to the distributing lines; and a protecting layer formed on the substrate except for the thin line unit having a predetermined region in order to seal the distributing units and the connecting units.